The ultrasound shows fluid-filled dilated loops of bowel. The next step is to perform a computed tomography (CT) scan of the patient’s abdomen, as well as a radiograph of the kidney, ureter, and bladder (KUB). The KUB radiograph (Figure 2) indicates small bowel obstruction with fluid filling the bowel.
Small bowel obstruction is a common and potentially fatal condition. Most cases occur in patients who have had prior abdominal or gynecologic surgery, but the most dangerous obstructions, those with a closed-loop that is blocked on both sides, often occur in patients who have not undergone any surgery.
The typical presentation of small bowel obstruction is abdominal pain, vomiting without diarrhea, and constipation, but a minority of patients may present atypically, without pain, vomiting, or constipation. Initially, pain may be intermittent, but as the obstruction worsens, the pain intensifies and becomes constant.
A high-grade obstruction will require surgery; signs of this type of obstruction include constant or severe pain, recurrent vomiting, tachycardia, soft blood pressure, fever, metabolic acidosis, leukocytosis, and elevated lactic acid, among others. The more conditions associated with a high-grade obstruction indicates a more severe prognosis and a reduced likelihood that conservative therapy with bowel rest and intravenous (IV) fluids will be effective.
The usual diagnostic test of choice for bowel obstruction is CT with IV contrast only. Oral contrast should be avoided as it can make visualization of ischemic bowel more difficult, can delay the CT scan, and can occasionally become aspirated in patients with a more intense condition. In patients with both low- and high-grade obstruction, CT may not be needed.
In patients with a high pretest probability of obstruction, bedside ultrasound or plain films may cinch the diagnosis and save time, which can save the patient’s life. In patients with low probability for obstruction but with recurrent vomiting, such as from suspected gastroparesis, hyperemesis from pregnancy or cannabis, or alcoholic ketoacidosis, plain films may be adequate to rule out small bowel obstruction with less radiation and an improved emergency department throughput.
Treatment of small bowel obstruction starts with intravenous fluids and nil by mouth status. In mild cases, these remedies may be sufficient. Nasogastric suctioning may help prevent surgery in more severe cases, but the literature support for this is scant. High-grade obstruction, obstruction with multiple red flags, or obstructions that worsen or fail to improve with 12 to 24 hours of conservative management will require operative intervention to minimize morbidity and avoid mortality.
The patient responded to fluid resuscitation and underwent surgical repair of the obstruction.
Brady Pregerson, MD, is an emergency physician at Cedars-Sinai Medical Center in Los Angeles and at Tri-City Medical Center in Oceanside, California.
Pregerson DB. Orthopedics: basics and open injuries. In: Emergency Medicine 1-Minute Consult Pocketbook. http://www.erpocketbooks.com/emergency_medicine_reference_books/quick-essentials-emergency-medicine/. 2017;5.